I am a huge fan of small puzzle and brain teaser games. No need to grind, no need to do daily tasks, just jumping in when I have some time to enjoy giving my mind some challenges and training. This is why I like PQ1 and the new PQ Immortal edition so much, because the “Puzzle” aspect is more significant and challenging than in PQ3.
If you are curious about quick puzzle games, these are my favorites for now.
PD: yes, I like sudokus a lot 